The present invention relates to an emergency wireless call system for vehicles on public highways and roads, and in particular to apparatus for testing the operability of the vehicle radio transmitter.
The increased number of motor vehicles used on the public highways and roads has resulted in the increased role of electronics in various traffic control and safety systems. An example of one of such systems is disclosed in the copending application, Ser. No. 446,590, filed on Feb. 28, 1974. In this application a wireless vehicle emergency call system is described which enables medical assistance, transport of injured people, and similar road services to be provided especially in sparsely settled and remote areas. An advantage of this system lies in the fact that the time needed for the arrival of the assistance, to cope with the energency situation, is shortened to an absolute minimum and the rescue and preservation of life is greatly increased, while damage caused by the accident is significantly minimized. The emergency assistance may be called for by any one, including those involved in the vehicular accident, passers by, or those drivers of other vehicles passing the scene of the incident, even though the passing vehicle does not stop at the scene.
The wireless vehicle emergency call system, described in the aforementioned application, includes vehicle transmitters of small size adapted to selectively emit a coded signal of a given mode indicative of the type of incident and the type of assistance required at the scene. Receivers, collecting the emitted signal, are spaced at predetermined intervals along the highway or road and are connected either by wire or by radio through a control center or a dispatching station which iniates the sending of the required assistance. To insure failsafe functioning of the entire system, it is essential that each of the components, primarily the vehicle transmitters, are in proper operative condition at all times. In a fully functioning system the number of vehicle transmitters is in theory unlimited and thus form the majority of the components of the system. However, since they are in the hands of ordinary vehicle drivers and electronically unskilled persons, they must be frequently checked for their correct operational characteristics. The testing of the vehicle transmitter must satisfy two basic requirements, in addition to other less significant requirements, namely, it must provide an appropriate indication of the coded signals or the mode of operation of the vehicle transmitter, and at the same time not interfere with the normal operation and reception of the collecting receivers of the system.
It is an object of the present invention to provide testing apparatus for vehicle transmitters satisfying at least the two major criteria set forth above.
It is a further object of the present invention to provide a testing device enabling the quick and continuous checking of the correct function of a large number of vehicle transmitters of a wireless emergency call system for vehicles on public highways and roads, without interfering with the normal emergency call system.
It is another object of the present invention to provide testing apparatus in which optical signals are produced according to the respective mode of the vehicle transmitter and thus capable of indicating the operation of the transmitter corresponding to the nature of the assistance to be called for by the emergency call system.
It is a further object of the present invention to provide test apparatus for a wireless emergency call system which is capable of blocking all interfering signals and thus conducting the test with respect only to the coded signals of the vehicle transmitter.
It is still another object of the present invention to provide testing device for emergency wireless call system which acts to dissuade the vehicle operator from attempting to check the functioning of the vehicle transmitter while driving on the highway or the road so that unintentional abuse of the wireless emergency call system is prevented.
The foregoing objects, other objects, as well as numerous advantages of the present invention will be apparent from the following disclosure of the invention.